Refillable multiple-fuse plug.



T. O. BERRY.

REFILLABLE MULTIPLE FUSE PLUG.

APPLICATION FILED MAR. 10, 1915.

Patented Oct. 10, 1916.

Thomas 0-B6r1y,'

WITNESSES ATTORN EY ffiwww.

THOMAS OWEN BERRY, OF COAHOMA, TEXAS.

BEFILLAIBLE MULTIPLE-FUSE PLUG.

Specification of Letters Patent.

Patented 0a. 10, 1916.

Application filed March 10, 1915. Serial N0. 13,442.

To all whom it may concern:

Be it known that I, THOMAS O. BERRY, a citizen of the United States, residing at Coahoma, in the county of Howard and -State of Texas, have invented a new and useful Refillable Multiple-Fuse Plug, of which the following is a specification.

This invention has reference to electrical fuse plugs and its object is to provide a multiple fuse plug of simple construction which may be made at a very low cost and used numerous times without recharging, and, moreover, may be recharged also at a very low cost.

In accordance with the present invention the fuse plug in its outward appearance may simulate fuse plugs as ordinarily constructed when each plug contains but a single fuse. The fuse chamber of the plug is provided with a readily removable cap and lodged in the chamber is a rotatable fuse having numerous arms any one of which may be brought into circuit so that in the event of the fuse blowing some other arm of fusible material may be moved into cire cuit closing position, so that the fuse plug is once more in condition for use, and this operation may be repeated as often as necessary or until all the fuses have been exhausted, when a new set of fuses is readily installed, the body of the fuse being available 1 for an indefinitely long time. Provision is also made for preventing arcing when a fuse blows, which arcing is liable to occur when the fuseis employed for protecting circuits carrying large currents.

The invention will be best understood from a consideration of the following detailed description, taken in connection with the accompanying drawings forming part of this specification, with the further understanding that while the drawings show a practical form of the invention, the latteris not confined to any strict conformity with the showing of the drawings, but may be changed and modified so long as such changes and modifications mark no material departure from the salient features of the invention.

In the 'drawings:Figure' 1 is an elevation of a fuse plug constructed in accordance with the present invention. Fig. 2 is a diametric section of the plug arranged to revent arcing. Fig. 3 is a View similar to Fig. 2 but taken on a slightly different plane and also illustrating a means differing from' Fig. 2 for preventing arcing. Fig. 4 is a plan view of the plug with the cover removed. Fig. 5 is a plan View of the plug with both the cover and the multiple fuse removed.

Referring to the drawings there is shown a body member 1 having a threaded stem 2 to which is applied a threaded shell 3 such as iscustomarily found in the socket-entering end of fuse plugs. The body 1 expands from the stem 2 and has a threaded exterior portion 4, the threads being the usual coarse rounded threads customarily em ployed in fuse plugs. Adapted to the threads 4 is a threaded sleeve 5 having an inturned flange 6 at one end adapted to override the corresponding end face of the body or head 1. Such face is formed just inside of its edge with a rabbet or groove 7 and with a central stud. Between the rabbet 7 and the central stud isa circular groove or channel 9 of appropriate depth and this channel may vary considerably in depth in accordance with the purposes of the plug. Extending axially through the body 1 and stem 2 is a rod 10 having a head 11 resting against the central stud, while at formed thereon either as part of the rod or the other end corresponding to the basic 'end of the stem 2 the rod 10 has a head 12 in the form of a washer soldered thereto or a even a drop of solder alone.

Lodged in the groove or rabbet 7 is a conducting plate 13 having spaced marginal tongues 14 projecting slightly over the groove 9. This conducting plate has a condoctor. 15 fast thereto and continued through the body 1 to a point close to the shell 3 where the conductor leaves the body and is connected to the shell 3 by solder 16 or otherwise.

Adapted to the groove 9 is a spider 17 of fusible material such as is customarily employed in fuse plugs, and the arms 8 of the spider which radiate from a common point terminate in expanded ends or heads 18 adapted to rest upon the plate 13 with the spider arm lodged between the tongues 14 and from thence curved into conformity with the groove 9, which latter is of rounded cross-section with its bottom curved. The heads 18 normally rest in the groove 7 and the center of the spider rests upon the head 11 of the rod or stem 10. Seated in the groove 7 in engagement with the heads 18 is a plate 19 of some suitable insulating material, preferably a plate of mica, since mica is not only electrically insulating, but is also refractory and more or less transparent. The mica plate 19 is held in place by the flange 6 of the clamp sleeve 5.

Leading from the bottom of the groove 9, or at any appropriate point in the groove, is a passage 20 opening through the head 1 preferably close to the stem or continuation 2.

With a fuse plug such as described, and especially where the fuse plug is employed for circuits carrying moderate currents, especially as to voltage, some arm of the spider 17 is so located that its head 18 is in engagement with the plate 13, while the center of the spider engages the head 11 of the rod 10. Considering the plug as installed, the electric circuit may be traced as passing by way of the rod 10 to the head 11, thence by the appropriate one of the arms of the spider 17 to the plate 13, thence by way of the conductor 15 to the shell 3 and from the latter again into the circuit. In the case of the passage of a current sufficiently heavy to fuse the fusible material the arm pf the spider then in the circuit is melted, and the circuit is broken in the customary way. To restore the continuity of the circuit or the availability of the fuse plug, the cap sleeve 5 is removed and the mica plate 19 is lifted away, whereupon the spider 17 is rotated until the next head 18 in order is brought into engagement with the plate 13. After this the removed parts are replaced and the plug is ready for further service. This may continue until all of the spider arms have been ruptured, which in the particular instance shown does not occur until six arms have been destroyed. When this finally does occur it is a simple matter to install a new spider when the plug is once more in operable condition.

When the fuse is employed for extra heavy currents Where arcing is liable to occur, and

this may occur where high voltages are employed, the channel or groove 9 may be filled With some non-conducting or refractory material, such as indicated at 21 in Fig. 3,

chalk representing such a material. Instead of chalk a ring 22 of porcelain or some such material may be lodged in the groove 9, as indicated in Fig. 2. In either case any tendency of the formation of an arc is very quickly stopped by the curved'path which the forming arc must of necessity follow, and since an arc does not readily follow a curved path it can progress but a very short distance before it is broken. Since the body of the fuse plug which is usually formed of porcelain or some other refractory insulating material, and the filling of the grooves are both insulating and refractory, no harm can occur from the are because of its very short duration, nor can the arc continue long enough to cause harm to the apparatus which the fuse plug is designed to protect since the obliteration of the are is practically instantaneous.

The fuse plug although capable of repeated use because of its multiple character need be no larger in size than the ordinary fuse plugs of commerce and may be manufactured at a correspondingly small cost, so that a fuse plug having the life of six ordinary plugs need co st but a trifle more than a single one of such ordinary plugs.

By varying the depth of the groove 9 the length of fusible material which may be installed therein is correspondingly varied, and the capacity of the plug can be likewise varied, but usually the plugs may have the grooves 9 of practically constant depth and the capacity of the fuses may be varied by varying the thiclmess of the arms of the spiders.

The passage 20 provides for the escape of any gases which maybe generated when a fuse blows, and thus prevent the generation of any back pressure within the plug.

The central part of the spider where the arms join may be utilized forv marking the capacity of the fuse. For instance, the numeral 6 would mean six amperes, 20 would mean twenty amperes, and soon.

What is claimed'is:

1. A multiple fuse plug'having a body member of refractory insulating material with a readily removable cap, said body member having an annular groove or recess at one end and at the same end provided with a central terminal and a side terminal, and fusible material in the form of a spider adapted to and rotatable in the recess about and in contact with the central terminal to bring any one of the arms of the spider into engagement with the side terminal.

2. A multiple fuse plug having a body "member of refractory insulating material witha readily removable. cap, said body 'member having an annular groove or recess at one end with a central terminal and a side terminal, and fusible material in the form of a spider adapted to the recess and rotatable therein about and in contact with the central terminal to bring any one of the arms of the spider into engagement with the side terminal, the spider being rotatable independently of both the cap and body member and the cap member constituting a clamp member for holding the spider of fusible material in any one of its adjusted positions.

3. A multiple fuse plug comprising a body member with an annular channel in one-end and there also provided with a central terminal, and another terminal at the side of the channel remote from the central terminal, and a unitary spider of fusible material mounted on the central terminal with its arms lodged in the channel and the ends of the arms extending outwardly therefrom,

4. A multiple fuse plug comprising a body member with a circular channel in one end and there also provided with a central terminal and another terminal in spaced relation thereto, and a spider of fusible material mounted for rotation on the central terminal with its arms lodged in the channel and having the ends .of the arms movable one at a time into engagement with the side terminal, said side terminal having means for engaging any one of the arms to prevent rotative movement of the spider,.

' arate from the body member and fuse spider and the fuse plug being provided with a readily removable cap constituting a clamp for the spider of fusible material for holding it in adjusted positions.

5. A multiple fuse plug comprising a body member with a screw plug extension all in one piece-and having the end remote from the screw plug extension provided with a readily removable cap and with-the face to which the cap is applied formed with a circular groove extending about a central stem and with a rabbet surrounding the groove, a contact on the central stem, a contact mounted in the rabbet, and an insulating plate adapted to the rabbet and held therein by the screw cap for clamping a multiple-member fuse in the groove with any one of its members in engagement with both contacts'simultaneously.

6. A multiple fuseplug comprising a body member with a screw plug extension all in one piece and having the end remote from the screw plug extension provided with a readily removable cap and with the face to which the cap is applied formed with'a circular groove about a central stem and with a rabbet surrounding the groove, a contact on the central stem, a contact mounted in the rabbet, and an insulating plate seated in the rabbet and held therein by the screw cap for clamping a fuse in the groove in engagement with the contacts, said fuse plug also being 'provided with a filler of refractory insulating material for the groove.

7 A fuse plug comprising a body member of refractory insulating material having a circular groove therein with .a marginal annular rabbet and a central and a single marginal contact, and a unitary rotatable spider of fusible material adapted to the groove and having its central portion in engagement with the central contact and theend of any one of its arms engaging the marginal contact.

8. A fuse plug comprising ber with a receptacle therein for a multiple fuse spider rotatable in the receptacle, contact terminals in the receptacle with one ofwhich the fuse spider when inserted is in constant contact and with the other of which any one of the fuses of .the spider may be brought individually into contact,"

and a cover member for the receptacle sepa body mem and movable to clamp the spider against both terminals in adjusted positions of said spider, said cover constituting the sole means for holding the fuse spider in the receptacle.

9. A fuse plug comprising a body meme ber of refractory insulating material with a cavity in one end and the other end adapted for insertion'in a fuse plug receptacle, the plug having contacts centrally and marginally located with respect to the cavity, and

a readily removable cap member for the cavity end of the plug related to the contacts to clamp a multiple fuse in the cavity in bridging relation to the contacts, whereby on the release of the clamping pressure the multiple fuse may be moved to bring different chosen parts thereof into bridging relation to the contacts.

'10. A multiple fuse plug havingan annularly continuous fuse receiving cavity and spaced contacts 1n operative relation to sand cavity, and a multiple fuse provided with a plurality of arms and rotatable in the fuse any one of said armsfinto 

